diff --git a/pkgs/servers/sql/postgresql/ext/periods.nix b/pkgs/servers/sql/postgresql/ext/periods.nix
index 9a390e258daf..102f80cf8d71 100644
--- a/pkgs/servers/sql/postgresql/ext/periods.nix
+++ b/pkgs/servers/sql/postgresql/ext/periods.nix
@@ -14,7 +14,7 @@ stdenv.mkDerivation rec {
   buildInputs = [ postgresql ];
 
   installPhase = ''
-    install -D -t $out/lib *.so
+    install -D -t $out/lib *${postgresql.dlSuffix}
     install -D -t $out/share/postgresql/extension *.sql
     install -D -t $out/share/postgresql/extension *.control
   '';